Method of preparing fluoroperhaloazaolefins

ABSTRACT

FLUOROPERHALOAZAOLEFINS ARE PREPARED BY REACTING A FLUOROPERHALOALKYL ISOCYANATE WITH A FLUOROPERHALOALKOXIIDE. FOR EXAMPLE, PERFLUORO-2,4-DIMETHYL-3-AZA-2-PENTENE IS PREPARED BY REACTING HEXAFLUOROISOPROPYL ISOCYANATE WITH POTASSIUM HEPTAFLUOROISOPROPOXIDE. THE FLUOROPERHALOAZAOLEFINS ARE USEFUL AS LIQUID DIELECTRICS AND AS INTERMEDIATES IN THE PREPARATION OF OTHER FLUORINATED ORGANIC COMPOUNDS.

United States Patent 3,751,469 METHOD OF PREPARING FLUORO- PERHALOAZAOLEFINS Bryce (I. Oxenrider, Florham Park, and Cyril Woolf,

Morristown, N.J., and Wilhelmus M. Beyleveld, Deventer, Netherlands, assignors to Allied Chemical Corporation, New York, N.Y.

No Drawing. Filed July 9, 1971, Ser. No. 161,336

Int. Cl. C07c 119/00 US. Cl. 260--566 R 9 Claims ABSTRAT OF THE DISCLOSURE Fluoroperhaloazaolefins are prepared by reacting a fluoroperhaloalkyl isocyanate with a fluoroperhaloalkoxide. For example, perfiuoro-2,4-dimethyl-3-aza:2pentene is prepared by reacting hexafluoroisopropyl isocyanate with potassium heptafluoroisopropoxide. The fluoroperhaloazaolefins are useful as liquid dielectrics and as intermediates in the preparation of other fluorinated organic compounds.

In accordance with this invention, fiuoroperhaloazaolefins having the formula Y": Y4 wherein Y Y Y and Y, are independently fluorine or fiuoroperhaloalkyl radicals haying either the formula CF X(CFX) wherein X is fluorine or chlorine and m is to 6, or the formula wherein X is chlorine or fluorine and n is 3 to 5, are prepared by reacting, under substantially anhydrous cond1- tions at a temperature ranging from about 40 C. to about 200 C., a fluoroperhaloalkyl isoeyanate having the formula wherein Y and Y are as defined above, with a fluoroperhaloalkoxide having the formula Ya F-(3-0M+ wherein Y, and Y, are as defined above and M represents the cation portion of the fluoroperhaloalkoxide.

The formation of the fiuoroperhaloazaolefin is represented by the following equation 3,751,469 Patented Aug. 7, 1973 an ionizable fluoride salt, as represented by the following equation wherein Y Y and M are as defined herein. Ionizable fluoride salts which form alcoholate salts with the carbonyl compound include potassium fluoride, rubidium fluoride, cesium fluoride, silver fluoride and tetra(lower alkyl) ammonium fluoride. Potassium fluoride is preferred.

If desired, the reaction mixture can be diluted with an inert, aprotic, polar, liquid diluent, such as acetonitrile, dimethylformamide, dimethylsulfoxide, dimethylacetamide, glycol ethers, cyclic polymethylene sulfones, and the like. Acetonitrile is preferred.

The reaction is preferably carried out at a temperature ranging from about 50 C. to about 150 C. The pressure employed is not critical and can be above or below atmospheric pressure as desired. However, the reaction is conveniently carried out at pressures autogenously developed at the reaction temperatures employed.

In the preferred embodiments of this invention, Y Y Y and Y, are independently fluorine or fiuoroperhaloalkyl radicals having the formula CF X(CFX) wherein X is fluorine or chlorine, preferably fluorine, and m is 0 to 6, preferably 0 to 3. Especially good results are oi tained when Y Y Y and Y, are trifluoromethyl.

The fluoroperhaloazaolefins of this invention are use ful as dielectric liquids for insulating electrical apparatus. They are employed in accordance with conventional methods for employing dielectric liquids.

The following examples further illustrate the invention. In each example, the reaction was carried out under sub stantially anhydrous conditions.

EXAMPLE 1 A sealed reactor containing 4.48 grams (0.02 mol) of poxide 4.2 grams (0.02 mol) of heptafluoroisopropyl isocyanate 30 ml. of acetonitrile (diluent) was maintained at C. for 21.5 hours. After the reaction mixture had been allowed to cool to room temperature, the volatile components were removed from the reaction mixture under a vacuum and collected. Infrared spectrum analysis indicated that the volatile components were perfluoro-2,4-dimethyl-3-aza 2 pentene, carbon dioxide, and some unreacted heptafluoroisopropyl isocyanate.

EXAMPLE 2 Dielectric constant, 1 kc. (ASTM D-) 1.83 Dielectric strength, kv./mil (ASTM D-877) 27.8 Dissipation factor, 1 kc. (ASTM D-ISO) 0.0005

potassium heptafluoroisopro- 3 We claim: 1. A process for preparing a fluoroperhaloazaolefin having the formula Y1 Y3 F+N=O/ Y Y4 wherein Y Y Y and Y; are independently fluorine or fluoroperhaloalkyl radicals having either the formula CF X(CFX) wherein X is fluorine or chlorine and m is to 6, or the formula ---CF(CFX) wherein X is chlorine or fluorine and n is 3 to 5, which process comprises reacting under substantially anhydrous conditions at a temperature ranging from about 40 C. to about 200 C., a fluoroperhaloalkyl isocyanate having the formula wherein Y and Y are as defined above and M represents the cation portion of the alkoxide selected from the group consisting of potassium, rubidium, cesium and silver.

2. The process of claim 2 wherein Y Y Y and Y; are independently fluorine or fluoroperhaloalkyl radicals having the formula CF (CFX) wherein X is fluorine or chlorine and m is 0 to 6.

3. The process of claim 2 wherein m is 0 to 3.

4. The process of claim 3 wherein X is fluorine.

5. The process of claim 4 wherein Y Y Y and Y; are trifluoromethyl.

6. The process of claim 1 wherein the temperature ranges from about C. to about C.

7. The process of claim 3 wherein the temperature ranges from about 50 C. to about 150 C.

8. The process of claim 7 wherein the reaction mixture contains an inert, aprotic, polar, liquid diluent.

9. The process of claim 8 wherein Y Y Y and Y, are trifluoromethyl.

References Cited UNITED STATES PATENTS 2,643,267 6/1953 Pearlson et al. 260-566 D 2,912,429 11/1959 Tullock 260566 D X LEON ZITVER, Primary Examiner G. A. SCHWARTZ, Assistant Examiner US. Cl. X.R. 260-566 F; 252-66 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3,751,469 Dated August 7, 1973 4 Patent No.

B. C. Oxenrider, C. Woolf and W. Beyleveld Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 6, "(F (CFX) should read -CF X(CFX) Signed and sealed this lstday of January 197 (SEAL) Atte st:

EDWARD M.FLETCHER,JR. RENE D. TEGTEEYER Attesting Officer Acting Commissioner of Patents 

